/* Voice Signal Preprocess
 * Copyright (C) 1991-2019 Nationalchip Co., Ltd
 *
 * crc32.c: from the zlib-1.1.3 distribution
 *
 */

/*
 * This file is derived from crc32.c from the zlib-1.1.3 distribution
 * by Jean-loup Gailly and Mark Adler.
 */

/* crc32.c -- compute the CRC-32 of a data stream
 * Copyright (C) 1995-1998 Mark Adler
 * For conditions of distribution and use, see copyright notice in zlib.h
 */

#include <stdint.h>
#include <stddef.h>

#define local static

#define __LITTLE_ENDIAN 1

#define  __BYTE_ORDER __LITTLE_ENDIAN
//#define __BYTE_ORDER __LITTLE_ENDIAN
//#define cpu_to_le32(x) (x)

//#include <compiler.h>

#define cpu_to_le32(x) (x)
#define le32_to_cpu(x) (x)
#define tole(x) cpu_to_le32(x)

#ifdef DYNAMIC_CRC_TABLE

local int crc_table_empty = 1;
local uint32_t crc_table[256];
local void make_crc_table OF((void));

/*
   Generate a table for a byte-wise 32-bit CRC calculation on the polynomial:
   x^32+x^26+x^23+x^22+x^16+x^12+x^11+x^10+x^8+x^7+x^5+x^4+x^2+x+1.

   Polynomials over GF(2) are represented in binary, one bit per coefficient,
   with the lowest powers in the most significant bit.  Then adding polynomials
   is just exclusive-or, and multiplying a polynomial by x is a right shift by
   one.  If we call the above polynomial p, and represent a byte as the
   polynomial q, also with the lowest power in the most significant bit (so the
   byte 0xb1 is the polynomial x^7+x^3+x+1), then the CRC is (q*x^32) mod p,
   where a mod b means the remainder after dividing a by b.

   This calculation is done using the shift-register method of multiplying and
   taking the remainder.  The register is initialized to zero, and for each
   incoming bit, x^32 is added mod p to the register if the bit is a one (where
   x^32 mod p is p+x^32 = x^26+...+1), and the register is multiplied mod p by
   x (which is shifting right by one and adding x^32 mod p if the bit shifted
   out is a one).  We start with the highest power (least significant bit) of
   q and repeat for all eight bits of q.

   The table is simply the CRC of all possible eight bit values.  This is all
   the information needed to generate CRC's on data a byte at a time for all
   combinations of CRC register values and incoming bytes.
   */
local void make_crc_table()
{
    uint32_t c;
    int n, k;
    uLong poly;        /* polynomial exclusive-or pattern */
    /* terms of polynomial defining this crc (except x^32): */
    static const Byte p[] = {0,1,2,4,5,7,8,10,11,12,16,22,23,26};

    /* make exclusive-or pattern from polynomial (0xedb88320L) */
    poly = 0L;
    for (n = 0; n < sizeof(p)/sizeof(Byte); n++)
        poly |= 1L << (31 - p[n]);

    for (n = 0; n < 256; n++)
    {
        c = (uLong)n;
        for (k = 0; k < 8; k++)
            c = c & 1 ? poly ^ (c >> 1) : c >> 1;
        crc_table[n] = tole(c);
    }
    crc_table_empty = 0;
}
#else
/* ========================================================================
 * Table of CRC-32's of all single-byte values (made by make_crc_table)
 */

local const uint32_t crc_table[256] = {
    tole(0x00000000L), tole(0x77073096L), tole(0xee0e612cL), tole(0x990951baL),
    tole(0x076dc419L), tole(0x706af48fL), tole(0xe963a535L), tole(0x9e6495a3L),
    tole(0x0edb8832L), tole(0x79dcb8a4L), tole(0xe0d5e91eL), tole(0x97d2d988L),
    tole(0x09b64c2bL), tole(0x7eb17cbdL), tole(0xe7b82d07L), tole(0x90bf1d91L),
    tole(0x1db71064L), tole(0x6ab020f2L), tole(0xf3b97148L), tole(0x84be41deL),
    tole(0x1adad47dL), tole(0x6ddde4ebL), tole(0xf4d4b551L), tole(0x83d385c7L),
    tole(0x136c9856L), tole(0x646ba8c0L), tole(0xfd62f97aL), tole(0x8a65c9ecL),
    tole(0x14015c4fL), tole(0x63066cd9L), tole(0xfa0f3d63L), tole(0x8d080df5L),
    tole(0x3b6e20c8L), tole(0x4c69105eL), tole(0xd56041e4L), tole(0xa2677172L),
    tole(0x3c03e4d1L), tole(0x4b04d447L), tole(0xd20d85fdL), tole(0xa50ab56bL),
    tole(0x35b5a8faL), tole(0x42b2986cL), tole(0xdbbbc9d6L), tole(0xacbcf940L),
    tole(0x32d86ce3L), tole(0x45df5c75L), tole(0xdcd60dcfL), tole(0xabd13d59L),
    tole(0x26d930acL), tole(0x51de003aL), tole(0xc8d75180L), tole(0xbfd06116L),
    tole(0x21b4f4b5L), tole(0x56b3c423L), tole(0xcfba9599L), tole(0xb8bda50fL),
    tole(0x2802b89eL), tole(0x5f058808L), tole(0xc60cd9b2L), tole(0xb10be924L),
    tole(0x2f6f7c87L), tole(0x58684c11L), tole(0xc1611dabL), tole(0xb6662d3dL),
    tole(0x76dc4190L), tole(0x01db7106L), tole(0x98d220bcL), tole(0xefd5102aL),
    tole(0x71b18589L), tole(0x06b6b51fL), tole(0x9fbfe4a5L), tole(0xe8b8d433L),
    tole(0x7807c9a2L), tole(0x0f00f934L), tole(0x9609a88eL), tole(0xe10e9818L),
    tole(0x7f6a0dbbL), tole(0x086d3d2dL), tole(0x91646c97L), tole(0xe6635c01L),
    tole(0x6b6b51f4L), tole(0x1c6c6162L), tole(0x856530d8L), tole(0xf262004eL),
    tole(0x6c0695edL), tole(0x1b01a57bL), tole(0x8208f4c1L), tole(0xf50fc457L),
    tole(0x65b0d9c6L), tole(0x12b7e950L), tole(0x8bbeb8eaL), tole(0xfcb9887cL),
    tole(0x62dd1ddfL), tole(0x15da2d49L), tole(0x8cd37cf3L), tole(0xfbd44c65L),
    tole(0x4db26158L), tole(0x3ab551ceL), tole(0xa3bc0074L), tole(0xd4bb30e2L),
    tole(0x4adfa541L), tole(0x3dd895d7L), tole(0xa4d1c46dL), tole(0xd3d6f4fbL),
    tole(0x4369e96aL), tole(0x346ed9fcL), tole(0xad678846L), tole(0xda60b8d0L),
    tole(0x44042d73L), tole(0x33031de5L), tole(0xaa0a4c5fL), tole(0xdd0d7cc9L),
    tole(0x5005713cL), tole(0x270241aaL), tole(0xbe0b1010L), tole(0xc90c2086L),
    tole(0x5768b525L), tole(0x206f85b3L), tole(0xb966d409L), tole(0xce61e49fL),
    tole(0x5edef90eL), tole(0x29d9c998L), tole(0xb0d09822L), tole(0xc7d7a8b4L),
    tole(0x59b33d17L), tole(0x2eb40d81L), tole(0xb7bd5c3bL), tole(0xc0ba6cadL),
    tole(0xedb88320L), tole(0x9abfb3b6L), tole(0x03b6e20cL), tole(0x74b1d29aL),
    tole(0xead54739L), tole(0x9dd277afL), tole(0x04db2615L), tole(0x73dc1683L),
    tole(0xe3630b12L), tole(0x94643b84L), tole(0x0d6d6a3eL), tole(0x7a6a5aa8L),
    tole(0xe40ecf0bL), tole(0x9309ff9dL), tole(0x0a00ae27L), tole(0x7d079eb1L),
    tole(0xf00f9344L), tole(0x8708a3d2L), tole(0x1e01f268L), tole(0x6906c2feL),
    tole(0xf762575dL), tole(0x806567cbL), tole(0x196c3671L), tole(0x6e6b06e7L),
    tole(0xfed41b76L), tole(0x89d32be0L), tole(0x10da7a5aL), tole(0x67dd4accL),
    tole(0xf9b9df6fL), tole(0x8ebeeff9L), tole(0x17b7be43L), tole(0x60b08ed5L),
    tole(0xd6d6a3e8L), tole(0xa1d1937eL), tole(0x38d8c2c4L), tole(0x4fdff252L),
    tole(0xd1bb67f1L), tole(0xa6bc5767L), tole(0x3fb506ddL), tole(0x48b2364bL),
    tole(0xd80d2bdaL), tole(0xaf0a1b4cL), tole(0x36034af6L), tole(0x41047a60L),
    tole(0xdf60efc3L), tole(0xa867df55L), tole(0x316e8eefL), tole(0x4669be79L),
    tole(0xcb61b38cL), tole(0xbc66831aL), tole(0x256fd2a0L), tole(0x5268e236L),
    tole(0xcc0c7795L), tole(0xbb0b4703L), tole(0x220216b9L), tole(0x5505262fL),
    tole(0xc5ba3bbeL), tole(0xb2bd0b28L), tole(0x2bb45a92L), tole(0x5cb36a04L),
    tole(0xc2d7ffa7L), tole(0xb5d0cf31L), tole(0x2cd99e8bL), tole(0x5bdeae1dL),
    tole(0x9b64c2b0L), tole(0xec63f226L), tole(0x756aa39cL), tole(0x026d930aL),
    tole(0x9c0906a9L), tole(0xeb0e363fL), tole(0x72076785L), tole(0x05005713L),
    tole(0x95bf4a82L), tole(0xe2b87a14L), tole(0x7bb12baeL), tole(0x0cb61b38L),
    tole(0x92d28e9bL), tole(0xe5d5be0dL), tole(0x7cdcefb7L), tole(0x0bdbdf21L),
    tole(0x86d3d2d4L), tole(0xf1d4e242L), tole(0x68ddb3f8L), tole(0x1fda836eL),
    tole(0x81be16cdL), tole(0xf6b9265bL), tole(0x6fb077e1L), tole(0x18b74777L),
    tole(0x88085ae6L), tole(0xff0f6a70L), tole(0x66063bcaL), tole(0x11010b5cL),
    tole(0x8f659effL), tole(0xf862ae69L), tole(0x616bffd3L), tole(0x166ccf45L),
    tole(0xa00ae278L), tole(0xd70dd2eeL), tole(0x4e048354L), tole(0x3903b3c2L),
    tole(0xa7672661L), tole(0xd06016f7L), tole(0x4969474dL), tole(0x3e6e77dbL),
    tole(0xaed16a4aL), tole(0xd9d65adcL), tole(0x40df0b66L), tole(0x37d83bf0L),
    tole(0xa9bcae53L), tole(0xdebb9ec5L), tole(0x47b2cf7fL), tole(0x30b5ffe9L),
    tole(0xbdbdf21cL), tole(0xcabac28aL), tole(0x53b39330L), tole(0x24b4a3a6L),
    tole(0xbad03605L), tole(0xcdd70693L), tole(0x54de5729L), tole(0x23d967bfL),
    tole(0xb3667a2eL), tole(0xc4614ab8L), tole(0x5d681b02L), tole(0x2a6f2b94L),
    tole(0xb40bbe37L), tole(0xc30c8ea1L), tole(0x5a05df1bL), tole(0x2d02ef8dL)
};
#endif

#if 0
/* =========================================================================
 * This function can be used by asm versions of crc32()
 */
const uint32_t * get_crc_table()
{
#ifdef DYNAMIC_CRC_TABLE
    if (crc_table_empty) make_crc_table();
#endif
    return (const uint32_t *)crc_table;
}
#endif

/* ========================================================================= */
# if __BYTE_ORDER == __LITTLE_ENDIAN
#  define DO_CRC(x) crc = tab[(crc ^ (x)) & 255] ^ (crc >> 8)
# else
#  define DO_CRC(x) crc = tab[((crc >> 24) ^ (x)) & 255] ^ (crc << 8)
# endif

/* ========================================================================= */

/* No ones complement version. JFFS2 (and other things ?)
 * don't use ones compliment in their CRC calculations.
 */
uint32_t crc32_no_comp(uint32_t crc, const unsigned char/*Bytef*/ *buf, unsigned int/*uInt*/ len)
{
    const uint32_t *tab = crc_table;
    const uint32_t *b =(const uint32_t *)buf;
    size_t rem_len;
#ifdef DYNAMIC_CRC_TABLE
    if (crc_table_empty)
        make_crc_table();
#endif
    crc = cpu_to_le32(crc);
    /* Align it */
    if (((long)b) & 3 && len) {
        uint8_t *p = (uint8_t *)b;
        do {
            DO_CRC(*p++);
        } while ((--len) && ((long)p)&3);
        b = (uint32_t *)p;
    }

    rem_len = len & 3;
    len = len >> 2;
    for (--b; len; --len) {
        /* load data 32 bits wide, xor data 32 bits wide. */
        crc ^= *++b; /* use pre increment for speed */
        DO_CRC(0);
        DO_CRC(0);
        DO_CRC(0);
        DO_CRC(0);
    }
    len = rem_len;
    /* And the last few bytes */
    if (len) {
        uint8_t *p = (uint8_t *)(b + 1) - 1;
        do {
            DO_CRC(*++p); /* use pre increment for speed */
        } while (--len);
    }

    return le32_to_cpu(crc);
}
#undef DO_CRC

uint32_t crc32 (uint32_t crc, const unsigned char/*Bytef*/ *p, unsigned int/*uInt*/ len)
{
    return crc32_no_comp(crc ^ 0xffffffffL, p, len) ^ 0xffffffffL;
}

